[CRYPTO] null: Add null blkcipher algorithm

This patch adds a null blkcipher algorithm called ecb(cipher_null) for
backwards compatibility.  Previously the null algorithm when used by
IPsec copied the data byte by byte.  This new algorithm optimises that
to a straight memcpy which lets us better measure inherent overheads in
our IPsec code.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 59 insertions, 10 deletions

diff --git a/crypto/crypto_null.c b/crypto/crypto_null.c
index 29f77477d701..fc2d2a4d7789 100644
--- a/crypto/crypto_null.c
+++ b/crypto/crypto_null.c
@@ -16,15 +16,17 @@
  * (at your option) any later version.
  *
  */
+
+#include <crypto/internal/skcipher.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/mm.h>
-#include <linux/crypto.h>
 #include <linux/string.h>
 
 #define NULL_KEY_SIZE           0
 #define NULL_BLOCK_SIZE         1
 #define NULL_DIGEST_SIZE        0
+#define NULL_IV_SIZE            0
 
 static int null_compress(struct crypto_tfm *tfm, const u8 *src,
                          unsigned int slen, u8 *dst, unsigned int *dlen)
@@ -55,6 +57,26 @@ static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
         memcpy(dst, src, NULL_BLOCK_SIZE);
 }
 
+static int skcipher_null_crypt(struct blkcipher_desc *desc,
+                               struct scatterlist *dst,
+                               struct scatterlist *src, unsigned int nbytes)
+{
+        struct blkcipher_walk walk;
+        int err;
+
+        blkcipher_walk_init(&walk, dst, src, nbytes);
+        err = blkcipher_walk_virt(desc, &walk);
+
+        while (walk.nbytes) {
+                if (walk.src.virt.addr != walk.dst.virt.addr)
+                        memcpy(walk.dst.virt.addr, walk.src.virt.addr,
+                               walk.nbytes);
+                err = blkcipher_walk_done(desc, &walk, 0);
+        }
+
+        return err;
+}
+
 static struct crypto_alg compress_null = {
         .cra_name               =       "compress_null",
         .cra_flags              =       CRYPTO_ALG_TYPE_COMPRESS,
@@ -96,6 +118,25 @@ static struct crypto_alg cipher_null = {
         .cia_decrypt            =       null_crypt } }
 };
 
+static struct crypto_alg skcipher_null = {
+        .cra_name               =       "ecb(cipher_null)",
+        .cra_driver_name        =       "ecb-cipher_null",
+        .cra_priority           =       100,
+        .cra_flags              =       CRYPTO_ALG_TYPE_BLKCIPHER,
+        .cra_blocksize          =       NULL_BLOCK_SIZE,
+        .cra_type               =       &crypto_blkcipher_type,
+        .cra_ctxsize            =       0,
+        .cra_module             =       THIS_MODULE,
+        .cra_list               =       LIST_HEAD_INIT(skcipher_null.cra_list),
+        .cra_u                  =       { .blkcipher = {
+        .min_keysize            =       NULL_KEY_SIZE,
+        .max_keysize            =       NULL_KEY_SIZE,
+        .ivsize                 =       NULL_IV_SIZE,
+        .setkey                 =       null_setkey,
+        .encrypt                =       skcipher_null_crypt,
+        .decrypt                =       skcipher_null_crypt } }
+};
+
 MODULE_ALIAS("compress_null");
 MODULE_ALIAS("digest_null");
 MODULE_ALIAS("cipher_null");
@@ -108,27 +149,35 @@ static int __init init(void)
         if (ret < 0)
                 goto out;
 
+        ret = crypto_register_alg(&skcipher_null);
+        if (ret < 0)
+                goto out_unregister_cipher;
+
         ret = crypto_register_alg(&digest_null);
-        if (ret < 0) {
-                crypto_unregister_alg(&cipher_null);
-                goto out;
-        }
+        if (ret < 0)
+                goto out_unregister_skcipher;
 
         ret = crypto_register_alg(&compress_null);
-        if (ret < 0) {
-                crypto_unregister_alg(&digest_null);
-                crypto_unregister_alg(&cipher_null);
-                goto out;
-        }
+        if (ret < 0)
+                goto out_unregister_digest;
 
 out:    
         return ret;
+
+out_unregister_digest:
+        crypto_unregister_alg(&digest_null);
+out_unregister_skcipher:
+        crypto_unregister_alg(&skcipher_null);
+out_unregister_cipher:
+        crypto_unregister_alg(&cipher_null);
+        goto out;
 }
 
 static void __exit fini(void)
 {
         crypto_unregister_alg(&compress_null);
         crypto_unregister_alg(&digest_null);
+        crypto_unregister_alg(&skcipher_null);
         crypto_unregister_alg(&cipher_null);
 }